Long-term effects of soil warming on soil respiration in subtropical and temperate forests

we experimentally warmed the surface soil of a subtropical (ST) and a warm temperate forest (WT) by ~ 1.5°C from 2012 to 2022 and compared the differences in SR, chemical stability of SOM, and microbial community composition between the two sites. Soil warming did not affect SR in the short term (2-3 years), but decreased it in the longer term (10 years) (-10.3%) at ST. Soil warming altered the chemical composition of SOM towards increased aliphaticity and decreased O-alkyl C content probably due to the elevated microbial K-strategist taxa at ST. At WT, soil warming significantly stimulated SR by 35.3% in the short term and by 29.8% in the longer term, mainly resulting from the enhanced decomposability of SOM (CC/MC) due to the substantial increase in fine root C input.

本研究于2012年至2022年间，对亚热带（subtropical, ST）与暖温带森林（warm temperate forest, WT）的表层土壤开展了约1.5℃的原位升温实验，并对比了两类林分间土壤呼吸（SR）、土壤有机质（Soil Organic Matter, SOM）化学稳定性以及微生物群落组成的差异。短期升温（2~3年）未对亚热带林分的土壤呼吸产生显著影响，但长期升温（10年）使其土壤呼吸降低10.3%。亚热带林分中，升温使土壤有机质的化学组成向脂肪族碳占比提升、氧烷基碳（O-alkyl C）占比降低的方向演变，这可能与该生境下微生物K-策略类群丰度升高密切相关。在暖温带林分中，土壤升温在短期显著刺激土壤呼吸达35.3%，长期亦使其提升29.8%，该现象主要源于细根碳输入量的显著增加，提升了土壤有机质（CC/MC）的可分解性。